....but I would, firstly, find and ring around a couple of piano restorers/specilaist music shops in your area for advice on the matter and see what they suggest.
I think its best to leave to experts if you value your piano.
Your welcome, Jo Jo........if the stains not too big an area maybe a repair would be inexpensive, but as to leave it to you to come up with the solution and try a repair yourself, you could end up making it worse, and i'm sure thats not what you want at all.
When you have time, call around and see what the experts say......could just need a polish with a special solution hopefully.
I would like to suggest you to contact with the professional cleaning companies which can offer you the best results.
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If the water damage has left a white cloudy stain it sounds as if the piano has been finished with french polishing, if this is the case it's relatively easy to restore it. I suggest you get a french polishing expert to examine it who will be able to restore it or suggest a reliable repairer if the finish is varnish.